Generally, a drum-type washing machine is a kind of washing machine that performs a washing operation using impact applied to laundry, which is put in a drum, dropping as the drum is rotated by a driving force of a motor under the condition that detergent and wash water are also put in the drum. The drum-type washing machine has various effects in that the laundry is struck and rubbed, there is little friction between the laundry and the drum, which minimizes damage to the laundry, and the laundry is not entangled.
Also, the drum-type washing machine has an advantage in that the consumption of wash water is considerably decreased as compared with a general pulsator-type washing machine. As a result, the demand of the drum-type washing machine has gradually increased as compared with the pulsator-type washing machine.
FIG. 1 is a perspective view illustrating the appearance of a conventional drum-type washing machine. The appearance of the drum-type washing machine is defined by a machine body 1 formed in the shape of a rectangular parallelepiped. Inside the drum-type washing machine is mounted a drum (not shown) in which laundry to be washed is put.
At the front part of the machine body 1 of the drum-type washing machine is mounted a door 2, by which the interior and the exterior of the washing machine selectively communicate with each other such that laundry is put into the drum or the laundry is removed from the drum out of the machine body 1.
At the upper side of the front part of the machine body 1 of the drum-type washing machine is mounted a control panel 3 including input buttons for allowing a user to input various operating conditions, such as washing courses and rinsing and spin-drying modes, and a display unit for displaying the remaining time.
At one side of the control panel is generally mounted a detergent box 4, in which detergent is stored.
FIG. 2 is a front view illustrating the control panel of the conventional drum-type washing machine. As shown in FIG. 2, the control panel 3 includes a plurality of buttons 8, a display window 5, a light emitting diode (LED) window 6 and a rotary knob 7.
The respective buttons 4 and the rotary knob 7 are input units for operating the washing machine. When a washing time, a washing course, and spin-drying and drying modes, are to be selected, a user manipulates the input units to input a desired washing course and a desired washing time.
The LED window 6 and the display window 5 serve to inform the user of various kinds of washing information, such as the washing progress and the remaining time. Specifically, the LED window 6 blinks to inform the user of the corresponding information, whereas the display window 5 displays characters or symbols to inform the user of the corresponding information.
The transmission of the information through the LED window is accomplished by a combination of blinking LEDs and the characters or the symbols printed at the front surface of the control panel corresponding to the blinking LEDs.
Inside the control panel 3 is mounted a controller, which functions as a control unit. FIG. 3 is an exploded perspective view illustrating the control panel 3 and the controller 10.
As shown in FIG. 3, the controller 10 includes pluralities of chips and circuit parts, a rotary knob, and a display unit 30. When the controller 10 is coupled with the control panel 3, the display unit 30 is first coupled to the control panel 3 through an insertion hole 9 formed in the control panel 3, and then the rotary knob 7 is inserted through the display unit 30. As a result, the rotary knob 7 is disposed at the front of the control panel 3.
The rotary knob 7 is a part frequently manipulated by a user. The rotary knob 7 is used to set the washing course or the washing time. Around the rotary knob 7 is mounted a lighting unit, such as LEDs, for clearly informing the user of the washing course or the washing time selected by the used.
Specifically, a plurality of LEDs 27 (see FIG. 4), which are selectively turned on according to the input of the rotary knob 7, and an LED supporter 25 for supporting the LEDs are mounted at a predetermined position of the controller 10 corresponding to the display unit 30.
Through the lighting unit, the user can clearly confirm the input state even in a dark room or in the night as well as in the daytime.
FIG. 4 is a sectional view illustrating the structure of the display unit of the conventional drum-type washing machine. As shown in FIG. 4, a rotary switch, which includes an encoder 20 and an encoder shaft 21 connected to the encoder 20, is mounted on the controller 10. The rotary knob 7, which is held and manipulated by a user, is coupled to the encoder shaft 21 of the rotary switch. Specifically, the user manipulates the rotary knob 7 mounted at the control panel 3 such that the user can input the operating conditions using the encoder 20 mounted at the controller 10 through the encoder shaft 21.
The rotary switch changes the number of pulses depending upon the right and left rotation amount of the rotary knob 7 coupled to the encoder shaft 21. The changed number of pulses is transmitted to a microprocessor (not shown) through the controller 10, whereby the washing machine is operated according to the corresponding operating conditions.
The LED supporter 25 is mounted on the controller 10 at the outside of the rotary knob 7 such that the LED supporter 25 surrounds the rotary knob 7.
At this time, the LED supporter 25 is constructed in a structure in which a plurality of LED location holes 26 are disposed along the circumferential direction in the shape of a ring, and the plurality of LEDs 27 are disposed in the LED location holes 26, respectively, as shown in FIGS. 3 and 4. Consequently, the LED location holes 26 serve as partitions to prevent interference between the blinking LED and the neighboring LEDs.
As shown in FIGS. 3 and 4, the display unit of the conventional drum-type washing machine is formed in the shape of a ring, and is disposed between the control panel 3 and the rotary knob 7. The display unit 30 is coupled with the inside part of the insertion hole 9 formed in the control panel 3 such that the rotary knob 7 can be inserted through the insertion hole 9.
In other words, hooks 33 formed at the inner surface of the control panel are inserted into grooves 32 formed at the edge of the display unit 30, respectively. After the display unit 30 is coupled to the control panel 3, the control panel 3 is coupled with the controller 10. Here, the coupling between the control panel 3 and the display unit 30 is accomplished by positioning the display unit 30 at the inside of the control panel 3 such that the hooks are aligned with the grooves, respectively, and pushing the display unit 30 toward the outside of the control panel 3.
Consequently, the rotary knob is inserted into the inside of the display unit, and therefore, the rotary knob is located at the front of the control panel.
Hereinafter, the principle of informing the user of the operating information through the display unit and the LEDs will be described.
The plurality of LEDs 27 are arranged around the rotary knob 7. As the rotary knob is rotated, the corresponding LED is turned on. The light generated from the turned-on LED is not scattered but is gathered through the corresponding LED location hole 26 of the LED supporter 25. In this connection, the display unit may be provided at predetermined positions thereof corresponding to the LED location holes 26 with display holes 31, through which light generated from the LEDs is gathered and emitted, or a predetermined semitransparent film.
In the case of forming the semitransparent film, the respective operating conditions are printed on the semitransparent film, and therefore, it is possible to clearly display the current operating conditions when the light generated from the LEDs is emitted. In the case of forming the display holes, the operating conditions are displayed at a predetermined position of the control panel corresponding to the display holes through which the light generated from the LEDs is emitted, thereby clearly displaying the current operating conditions.
Recently, on the other hand, there has been provided a drum-type washing machine constructed in a structure in which the temperature of wash water is increased to the temperature level set by a user, and the wash water having the increased temperature is supplied into the drum to perform a washing operation, thereby accomplishing more effective washing. For example, this kind of drum-type washing machine has a boiling function to increase the temperature of the wash water to approximately a boiling point and then perform a washing operation.
In this kind of drum-type washing machine, therefore, the selection of the washing course and the input of the temperature of the wash water are performed by the rotary knob. This kind of control panel 3 is shown in FIG. 2.
The display unit 30 is disposed around the rotary knob 7, and the display unit 30 is divided into a plurality of wash water temperature display parts 34 in the circumferential direction such that the temperatures of the wash water are displayed on the respective wash water temperature display parts 34. At the front surface of the control panel surrounding the display unit 30 are disposed washing course display parts 35, on which washing courses are displayed corresponding to the divided wash water temperature display parts 34.
FIG. 2 illustrates, for example, seven divided washing course display parts 35. According to the respective washing courses, at least one temperature of the wash water is displayed on the display unit 30.
As shown in FIG. 2, the user can input one of the washing courses displayed on the control panel by rotating the rotary knob. In the respective washing courses, the rotation angle of the rotary knob is divided, whereby it is possible for the user to input the temperature of the wash water displayed on the display unit according to the rotation angle.
Specifically, it is possible for user to input composite operating conditions, such as the washing courses displayed on the control panel and the temperature of the wash water displayed on the display unit, using a single rotary knob. In other words, when the user rotates the rotary knob to a specific position, the washing courses and the temperature of the wash water, i.e., the composite operating conditions of the washing machine, are inputted correspondingly.
On the other hand, the composite operating conditions of the washing machine may include the water level of the wash water, the washing time, or the RPM of the drum at the time of the spin-drying operation.
In other words, it is possible to input the composite operating conditions, including the washing courses, the temperature of the wash water, the RPM of the drum at the time of the spin-drying operation, using a single rotary knob.
In the conventional drum-type washing machine illustrated in FIGS. 1 to 4, however, the display unit for displaying the operating conditions of the washing machine inputted by the rotary knob is directly coupled to the control panel with the result that it is difficult to adjust the gap d between the display unit and the LED supporter.
Specifically, the gap d is formed between the display unit and the LED supporter as shown in FIG. 4, and therefore, the light emitted from the corresponding LED leaks through the gap d. As a result, the intensity of the light is decreased, or it is difficult to confirm which condition the light emitted from the corresponding LED indicates.
When the diameter of the display unit is increased, the light may leak in the circumferential direction as well as in the radial direction. In this case, the above-mentioned problems become more serious.
In order to solve the problems, it may be possible to interrupt the light interference by transmitting the light through a specific region of the display unit and preventing the light from being transmitted through other regions of the display unit. In this case, however, the costs for manufacturing the display unit are greatly increased.